The invention relates to wind powered ventilators adapted to be mounted on the roof of a building.
Rotary-type turbine ventilators have long been used. Generally, the known devices either take the shape of a large sphere having open vanes which are angled whereby to be moved in a rotational manner by wind velocity.
Certain other styles of roof ventilators utilize windmill-type fan blade assemblies which are similarly rotated by wind currents.
A few of the known prior art ventilators have included secondary ventilating means in the form of a fan assembly mounted along the rotating shaft of the turbine, sometimes in association with a mounting collar which supports the device on the roof. The roof mounting structure remains static while the turbine rotates closely therearound.
Particular problems with known rotary turbine ventilators involve the open vane structures in that water may intrude into the building structure below.
Additionally, conventional turbine-type roof ventilators provide very unsightly large spherical turbines, or hats, which makes their use in residential construction less appealing.
The prior art devices also provide for the close rotating association of the turbine with respect to the stationary collar. Thus, noise caused by vibration between the spinning turbine and collar have made this construction less desirable.
By using closely spaced turbine blades, certain prior art constructions require that the turbine must spin in order to ventilate the structure. If wind speeds are very slight, or if the shaft bearings freeze up, these kinds of devices fail to effectively provide sufficient air space for the heated air in an attic, or other structure below, to be evacuated. This is compounded inasmuch as should the weather become inclement, the immobile turbine allows rain, sleet or snow to enter the structure, which can result in water damage to the building.
Accordingly, the present invention provides a significant improvement and an advance in the art of wind powered ventilators by providing a low profile turbine in the form of a relatively flat hood or dome.
In furtherance of the solutions to the problems found in the prior art, the present invention provides a turbine having closed louvers, or fins, to be driven by the wind so that rain, sleet or snow is prevented from entering into the structure below.
The invention utilizes a large fan blade assembly affixed to the rotating shaft within the mounting collar. The fan blade assembly may be provided with a large diameter which is only slightly less than the mounting collar to achieve a very forceful evacuation of air for the efficient ventilation of the structure below.
The present invention includes a low profile turbine and yet provides an enlarged ventilating space between the turbine and the mounting collar whereby even during diminished wind conditions, heated air may still be ventilated from the structure below.
An additional benefit is found wherein the large spacing between the turbine and mounting collar prevents the rotating turbine from noisily contacting the edge of the mounting collar as it is being rotated by the wind.
The invention further allows for the quick removal of the turbine from an associating rotating shaft whereby bearings arranged with the shaft may be easily lubricated when needed.
The weather-resistant features of the invention are also enhanced by the capability of the close-louvered turbine to vertically overlap the upper rim of the mounting collar in order to impede the intrusion of rain during windy conditions in which the rain might be forcibly thrust in all directions.